Linear motor mounted press machine and press working method

ABSTRACT

The present invention provides a linear motor mounted press machine that allows both a punch and a die to be driven to enable various types of machining, the linear motor mounted press machine having a simple configuration and enabling accurate machining. The present invention is applied to a press machine that performs a press working on a workpiece W by means of a punch  61  and a die  62 . A punch linear motor  1  is installed in an upper frame  41   b  of a press frame  41  to drivingly elevate and lower the punch  61 . A die linear motor  1 A is installed in a lower frame  41   c  of the press frame  41  to drivingly elevate and lower the die  62.

FIELD OF THE INVENTION

The present invention relates to a press machine such as a punch presswhich uses linear motors as a driving source, and a press working methodfor performing a press working by using the press machine.

BACKGROUND OF THE INVENTION

Press machines such as punch presses commonly use, as a press drivingsource that moves punches forward and backward, a mechanism thatconverts rotary motion of rotary type electric motors into rectilinearmotion via a crank mechanism and so on, or hydraulic cylinders. Aproposal has also been made of press machines using servo motors aselectric motors to vary punch speed during strokes.

However, press machines using rotary type electric motors require amechanism that converts rotary motion into rectilinear motion and thushave complicated configurations. Further, since rotary motion isconverted into rectilinear motion, lost motion or the like may occur,degrading controllability. Press machines using a hydraulic cylinderrequire a hydraulic supply system such as a hydraulic unit and thus havecomplicated structures.

Attempts have also been made to use linear motors as a press drivingsource. When used to drive punches, linear motors, unlike rotary typemotors, eliminate the use of a mechanism that converts a rotation into arectilinear motion. The linear motor thus reduces the number of partsrequired and simplifies the structure.

Some conventional punch presses are used for a forming process. It iswell known that punch presses can be commonly used for hole making andshape forming. Some punch presses include a die constituting a lowertool and configured as a recessed tool, and a punch configured as aprojecting tool, to perform shape forming on a plate-like workpiece suchthat the work piece has a portion projecting from its bottom surface.The portion resulting from the shape forming projects from the bottomsurface of the workpiece and may thus interfere with feeding of theworkpiece on a table.

On the other hand, some commercialized punch presses include a dieconstituting a lower tool, and configured as a projecting tool, and apunch configured as a recessed tool as opposed to the above pressmachines, to perform shape forming on the workpiece such that theworkpiece has a portion projecting from its top surface. When the die isthus configured as a projecting tool and always projects above a dieheight, the bottom surface of the workpiece may be damaged by the diewhen the workpiece is fed. A proposal has thus been made of punchpresses which normally allow such a projecting shape forming die tostand by below the die height and which project the die above the dieheight during operation (for example, the Unexamined Japanese PatentApplication Publication (Tokkai-Hei) No. 11-156459). The die is elevatedand lowered by a cylinder device that moves forward and backward in ahorizontal direction and a cam, a link mechanism, or the like whichconverts the horizontal operation of the cylinder device into a verticaloperation.

In the conventional press machines using linear motors, the punch isdriven, and the die is fixed. When such a press machine has ashape-forming or hole-making die installed so as to be able to elevateand lower in order to provide multiple functions, where a cylinderdevice is used as a mechanism for elevating and lowering the die,elevating and lowering strokes are fixed. This precludes the formingprocess such that the resulting workpieces have different projectionheights. Press machines using servo motors and ball screws as a dieelevating and lowering mechanism can achieve the forming process suchthat the resulting workpieces have different projection heights.However, these press machines have complicated configurations like thosewhich drive the punch.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a linear motormounted press machine that allows both a punch and a die to be driven toenable various types of machining, the linear motor mounted press havinga simple configuration and enabling accurate machining. It is anotherobject of the present invention to provide high power while avoidingdifficulties with manufacture. It is yet another object of the presentinvention to facilitate discharge of slag resulting from hole making orthe like while enabling the die to be driven by a linear motor locatedimmediately below the die. It is still another object of the presentinvention to drive both the die and the punch to machine a workpiece,enabling various types of machining.

A linear motor mounted press machine in accordance with the presentinvention presses a workpiece using a punch and a die both located in apress drive axis center. The press machine comprises a press framehaving an upper frame and a lower frame, a punch linear motor providedin the upper frame to drivingly elevate and lower the punch, and a dielinear motor provided in the lower frame to drivingly elevate and lowerthe die.

This configuration uses the linear motor to drivingly elevate and lowerthe punch. Thus, unlike configurations using rotary type motors, thisconfiguration eliminates the need for a mechanism that converts therotation into the rectilinear motion. This reduces the number of partsrequired and simplifies the structure of the press machine. Further, thedie is also drivingly elevated and lowered by the linear motor. Thus,compared to configurations that drivingly elevate and lower the die viaa horizontal cylinder device and a cam, a link mechanism, or the like,this configuration is simple and offers excellent controllability toallow die elevating and lowering strokes to be accurately controlled.This configuration thus allows both the punch and the die to be drivento enable various types of machining and drives both the punch and thedie using the linear motor. This simplifies the configuration andenables accurate machining.

In the present invention, one or both of the punch linear motor and thedie linear motor may be unit linear motor assemblies each including aplurality of unit linear motors around the press drive axis center, eachof the unit linear motors having an output shaft that is parallel to thepress drive axis center. Punch working may require a high thrust. Linearmotors generally use permanent magnets with a strong magnetic force.However, it is difficult to manufacture motors each providing a highthrust owing to the manufacturing limit on the size of magnets,limitations on supply voltage, or the like. However, the assembly of theplurality of unit linear motors described above allows the power of theindividual unit linear motors to be collectively utilized, providing thehigh power.

In the present invention, the die linear motor may have a hole in anarea thereof which coincides with the press drive axis center, slagresulting from the press working being discharged from the hole. Thepress drive axis center corresponds to the center of a ram shaft, thatis, the center of the punch and die. The die-side liner motor is locatedbelow the die. Thus, the die-side linear motor does not pose any problemduring shape forming but may interfere with discharge of slag duringhole making. Accordingly, the hole for slag discharge is formed in thearea of the die linear motor which coincides with the press drive axiscenter. This enables slag to be smoothly discharged while the die isbeing driven using the linear motor.

In particular, where the die linear motor is a unit linear motorassembly including a plurality of unit linear motors around the pressdrive axis center, each of the unit linear motors having an output shaftthat is parallel to the press drive axis center, the die linear motorpreferably has a hole in an area thereof which coincides with the pressdrive axis center, slag resulting from the press working beingdischarged from the hole. Where the die linear motor is the assembly ofthe unit linear motors, the press machine can be easily configured sothat the hole for slag discharge is formed in the press drive axiscenter.

The linear motor mounted press machine in accordance with the presentinvention may comprise a control means for drivingly elevating andlowering both the punch and the die relative to the workpiece forperforming the press working. Various types of machining can beperformed on the workpiece by simultaneously driving both the punch andthe die or sequentially driving the punch and the die to machine onepoint. When both the punch and the die are thus drivingly elevated andlowered for the press working, the excellent controllability of thelinear motors can be effectively utilized. Therefore, the presentinvention, using the linear motor as a driving source for both the punchand the die, can effectively increase accuracy.

A press working method in accordance with the present invention uses thelinear motor mounted press machine having one of the aboveconfigurations, and to drivingly elevate and lower both the punch andthe die relative to the workpiece for performing the press working.According to this method, the linear motor mounted press machine inaccordance with the present invention, using the linear motor as adriving source for both the punch and the die, can effectively increaseaccuracy, and this allows various types of punch working to beaccurately performed. The term “punch working” as used herein refers tohole making or shape forming.

The linear motor mounted press machine in accordance with the presentinvention performs the press working on the workpiece by means of thepunch and the die both located in the press drive axis center. Thelinear motor mounted press machine comprises the press frame having theupper frame and the lower frame, the punch linear motor provided in theupper frame to drivingly elevate and lower the punch, and the die linearmotor provided in the lower frame to drivingly elevate and lower thedie. This configuration thus allows both the punch and the die to bedriven to enable various types of machining. In spite of this function,the configuration is simple and enables accurate machining.

When one or both of the punch linear motor and the die linear motor arethe unit linear motor assemblies each including the plurality of unitlinear motors around the press drive axis center, each of the unitlinear motors having the output shaft that is parallel to the pressdrive axis center, the difficulties with the manufacture of the linearmotors can be avoided, and high power is provided.

Where the die linear motor has a hole in an area thereof which coincideswith the press drive axis center, slag resulting from the press workingbeing discharged from the hole, then slag resulting from hole making orthe like can be easily discharged, while enabling the die to be driven.

Where the die linear motor is a unit linear motor assembly including aplurality of unit linear motors around the press drive axis center, eachof the unit linear motors having the output shaft that is parallel tothe press drive axis center, and the die linear motor has a hole in anarea thereof which coincides with the press drive axis center, slagresulting from the press working being discharged from the hole, thenthe difficulties with the manufacture of the linear motors can beavoided, and the high power is provided. Further, slag resulting fromhole making or the like can be easily discharged.

Where the linear motor mounted press machine includes a control meansfor drivingly elevating and lowering both the punch and the die relativeto the workpiece for performing the press working, various types ofmachining can be performed on the workpiece by driving both the die andthe punch to machine the workpiece. Furthermore, the machining can beaccurately performed.

The press working method in accordance with the present inventionperforms the press working by using the linear motor mounted pressmachine of the present invention, to drivingly elevate and lower boththe punch and the die relative to the workpiece. Various types ofmachining can thus be performed on the workpiece by driving both the dieand the punch to machine the workpiece. Furthermore, the machining canbe accurately performed.

Other features, elements, processes, steps, characteristics andadvantages of the present invention will become more apparent from thefollowing detailed description of preferred embodiments of the presentinvention with reference to the attached drawing.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded side view of a linear motor mounted press machinein accordance with an embodiment of the present invention.

FIG. 2 is a vertical sectional view of a punch linear motor in the pressmachine.

FIG. 3 is a sectional view of the punch linear motor along line III-IIIin FIG. 2.

FIG. 4 is a vertical sectional view of a die linear motor in the pressmachine.

FIG. 5 is a diagram illustrating the operation of the press machine.

FIG. 6 is a vertical sectional view of a variation of the die linearmotor in the press machine.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

An embodiment of the present invention will be described with referenceto FIGS. 1 to 5.

The press machine is a punch press that uses a punch 61 and a die 62 toperform a press working on a plate-like workpiece W such as a sheetmetal. The press machine comprises a press frame 41, a punch linearmotor 1 provided in an upper frame 41 b of the press frame 41 to elevateand lower the punch 61, and a die linear motor 1A provided in a lowerframe 41 c to elevate and lower the die 62.

The press frame 41 comprises the upper frame 41 b, the lower frame 41 cand a column portion 41 a to which the upper frame 41 b and the lowerframe 41 c are coupled, and the press frame 41 is open in a frontsurface and has a C-shaped side surface. A vertical pair of toolsupports 42, 43 and a workpiece feeding mechanism 44 are installedbetween the upper frame 41 b and the lower frame 41 c. A press mechanism45 using the punch linear motor 1 as a driving source is installed inthe upper frame 41 b. The press frame 41 may be a gate-, ring-, orhollow-rectangle-like frame in which the upper and lower frame portionswith an equivalent length are coupled together at a front end and a rearend by the column portion.

The tool supports 42, 43 comprise an upper turret and a lower turretwhich are concentrically installed and each of which has punches 61 anddies 62 mounted at a plurality of points in a circumferential directionthereof. Rotation of the tool supports 42, 43 allows each of the punches61 and the dies 62 to be indexed to a predetermined punch position P.

In FIG. 1, the workpiece feeding mechanism 44 uses a workpiece holder 47to grip an edge of the plate like workpiece W to move it on a table 48forward, backward, rightward, and leftward.

The press mechanism 45 supports a ram 49 that elevates and lowers thepunch 61 indexed to the punch portion P in the tool support 42 so thatthe ram 49 can be freely elevated and lowered by a ram guide 50. The ram49 is drivingly elevated and lowered by an output shaft 12 of the linearmotor 1.

As shown in FIG. 2 and FIG. 3, the punch linear motor 1 has a pluralityof unit linear motors 2 composed of cylindrical linear motors andjuxtaposed in a motor case 25. In this example, the juxtaposition formis such that the cylindrical linear motors 2 made in accordance with thesame specifications are arranged on a virtual circle around the center 0of the output shaft, that is, a press drive axis center, in itscircumferential direction.

Each of the unit linear motors 2 comprises a shaft member 3 composed ofa permanent magnet having alternately arranged N pole and S pole, and acoil unit 4 through which the shaft member 3 is movable in an axialdirection relative to the coil unit 4. The coil unit 4 is composed of aplurality of coils 5 arranged in a cylindrical coil case 7 in the axialdirection and surrounding the shaft member 3. The coil unit 4constitutes a stator, and the shaft member 3 constitutes the outputshaft of the motor 2, which constitutes a moving member of the unitlinear motor 2. The shaft member 3 is composed of one round bar-likemember but may be composed of a plurality of permanent magnets arrangedin the axial direction.

The motor case 25 has an inner cylinder 26 and an outer cylinder 27arranged concentrically with each other, and end plates 28, 29 thatcouple the opposite ends of the inner cylinder 26 and the outer cylinder27 together. The unit linear motors 2 are arranged in the annular spacebetween the inner cylinder 26 and the outer cylinder 27 in thecircumferential direction. The opposite ends plates 28, 29 have aplurality of shaft member insertion holes 28 a, 29 a through which theshaft member 3 of each unit linear motor 2 is inserted, and the endplate 28 has a guide shaft insertion hole 28 b in its center.

The shaft members 3 of the unit linear motors 2 are coupled together attheir opposite ends by coupling members 10, 11, and the plurality ofshaft members 3 and the coupling members 10, 11 constitute a movingmember 30. The coupling member 11 of the moving member 30 has the outputshaft 12 located in the center 0 of the arrangement of the unit linearmotors 2.

A guide mechanism 32 is provided between the motor case 25 and themoving member 30 to guide movement of the shaft members 3 of theplurality of unit linear motors 2. The guide mechanism 32 is composed ofan inner cylinder 26 of the motor case 25, a bush 15 that is a guideportion fixedly fitted into the inner cylinder 26, and a guide shaft 13,as a guided portion, provided at the center of one end side of thecoupling member 10 and fitted into a bush 15 so as to be movable in theaxial direction. The bush 15 constitutes a sliding shaft. Instead of thebush 15, a direct-acting roll bearing may be interposed.

The guide mechanism 32 has a rotation inhibiting means 16 for inhibitingrotation of the moving member 30 relative to the motor case 25. Therotation inhibiting means 16 comprises a key groove 17 formed in theguide shaft 13 along the axial direction and a key portion 18 fixed tothe inner cylinder 26 of the motor case 25 and slidably engaged with thekey 17.

FIG. 4 shows the die linear motor 1A. The die linear motor 1A has a slagdischarge hole 70 formed in its center. Each unit linear motor 2 has abush 15A in place of the guide mechanism 32 of the punch linear motor 1in FIG. 2 and FIG. 3. The slag discharge hole 70 comprises the internalspace in the inner cylinder 26 of the motor case 25. The center of theslag discharge hole 70 coincides with the press drive axis center thatis the center of the punch position P.

The coupling member 11 on an output side of the die linear motor 1A hasan output shaft 12A comprising a hollow shaft and internallyconstituting a slag discharge hole, the output shaft 12A projectingupward. The remaining part of the configuration of the die linear motor1A is similar to that of the punch linear motor 1, described withreference to FIG. 2 and FIG. 3, and duplicate descriptions are thusomitted.

The punches 61 installed on the upper tool support 42 and the dies 62installed on the lower tool support 43 in FIG. 1 include a punch 61 ₁and a die 62 ₁ for hole making shown in FIG. 5A and a punch 61 ₂ and adie 62 ₂ for shape forming shown in FIG. 5B and FIG. 5C. The hole-makingpunch 61 ₁ is fixedly installed on the lower tool support 43 via a dieholder 63.

The shape-forming punch 61 ₂ is recessed and has a recessed portion 65on its bottom surface. The shape forming die 62 ₂ is projecting and hasa projecting portion 66 at the top. The shape forming die 62 ₂ isinstalled so as to be able to elevate from and lower to the die holder63, installed on the lower tool support 43. In a lowered condition, theshape forming die 62 ₂ is located below a die height DH. The shapeforming die 62 ₂ is pushed up above the die height DH by the outputshaft 12A of the die linear motor 1A.

The shape forming die 62 ₂ has an output shaft engaging projection 67provided on its bottom surface. During elevation, an upper end of theoutput shaft 12A of the die linear motor 1A is pressed against thebottom surface of the output shaft engaging projection 67. The shapeforming die 62 ₂ is urged downward by a return spring (not shown in thedrawings).

A hollow hole 69A is formed at the installation position of each die 62of the lower tool support 43, comprising a turret; the output shaft 12Aof the die linear motor 1A is advanced through the hollow hole 69A so asto be able to elevate and lower. A bolster 68 that receives the toolsupport 43 comprises a pair of bolster components, and the area betweenthe bolster components constitutes a hollow space 69B through which theoutput shaft 12A of the die linear motor 1A is advanced so as to be ableto elevate and lower.

In FIG. 1, a control device 81 controlling the press machine comprises acomputerized numerical control device, and the control device 81 has anarithmetic control section 83 that analyzes and executes a processingprogram 82. The control device 81 thus gives instructions to the linearmotors 1, 1A, servo motors for shafts of the workpiece feeding mechanism44, and a driving source (not shown in the drawings) for indexationrotation of the tool supports 42, 43. The control device 81 has acontrol means 84 for drivingly elevating and lowering the punches 61 andthe dies 62 by means of the linear motors 1, 1A for performing the pressworking. The control means 84 is composed of instructions described inthe processing program 82 as well as the arithmetic control section 83.

A description will be given of the operation of the press machineconfigured as described above.

As shown in FIG. 5A, the die linear motor 1A is normally in the loweredcondition, and the upper end of the output shaft 12A is located belowthe bottom surface of the lower tool support 43. This enables the toolsupport 43, comprising a turret, to be rotated without interfering withthe output shaft 12A. Further, as shown in FIG. 5B, the upper end of theform-shaping die 62 ₂ is located below the die height DH. In thiscondition, the upper tool support 42 and the lower tool support 43 arerotated to index any of the punches 61 and the dies 62 to the punchposition P. This prevents the shape-forming die 62 ₂ from coming intosliding contact with the bottom surface of the workpiece W to damage it.

Punch working such as normal hole making is performed by drivinglylowering the punch 61 of the upper tool support 42 by means of the punchlinear motor 1 with the die linear motor 1A thus lowered. Slag resultingfrom hole making falls down from the machine through the slag dischargehole 70, formed in the center of the die linear motor 1A.

For shape forming, the upper tool support 42 and the lower tool support43 are rotated to index the shape forming die 62 ₂ to the punch center Pas shown in FIG. 5B. This positions the shape forming die 62 ₂immediately above the output shaft 12A of the die linear motor 1A. Inthis condition, as shown in FIG. 5C, the die linear motor 1A is allowedto perform elevational driving so that its output shaft 12A elevates theshape-forming die 62 ₂ to a predetermined height. Further, theshape-forming punch 61 ₂ is lowered by the punch linear motor 1 so as tosandwich the workpiece W between the shape-forming punch 61 ₂ and theshape-forming die 62 ₂. This allows a shape forming portion Wa to beformed in the workpiece W by pressing.

Once shape forming is finished, the punch linear motor 1 is elevated,and the die linear motor 1A is lowered. Thus, the shape forming portionWa formed by the punch working projects upward from the workpiece W andthus does not interfere with feeding of the workpiece W on the table 48by means of the workpiece feeding mechanism 44.

The press machine configured as described above uses the linear motor 1as a press driving source. Compared to press machines using rotarymotors, this press machine thus does not need any mechanism thatconverts the rotation into the rectilinear motion of the ram 49, andthis also reduces the number of parts required for the press mechanism45 and simplifies its configuration. Further, compared to press machinesusing a hydraulic cylinder as a press driving source, this press machineeliminates the need for the hydraulic unit, simplifying theconfiguration. Furthermore, the linear motor 1 offers excellentpositional accuracy, enabling high-quality, accurate machining.

The shape forming die 62 ₂ is also drivingly elevated and lowered by thelinear motor 1A. Thus, compared to conventional press machines using ahorizontal cylinder device and a cam, a link mechanism, or the like forelevating and lowering driving, this press machine has a simpleconfiguration, offers excellent controllability, and enables theaccurate control of the elevating and lowering strokes of theshape-forming die 62 ₂. Thus, both the punch 61 and the die 62 can bedriven to enable various types of machining, and the linear motors 1, 1Aare used to drive the punch 61 and the die 62, respectively. Thissimplifies the configuration and enables accurate machining.

Each of the punch linear motor 1 and the die linear motor 1A is the unitlinear motor assembly including the plurality of unit linear motors 2around the press drive axis center; each of the unit linear motors 2 hasthe output shaft that is parallel to the press drive axis center. Thisprovides high power. Punch working may require a high thrust. However,the linear motors generally use permanent magnets with a strong magneticforce. Accordingly, it is difficult to manufacture motors each providinga high thrust owing to the manufacturing limit on the size of magnets,limitations on supply voltage, or the like. However, in the presentembodiment, each of the linear motors 1, 1A includes the assembly of theplurality of unit linear motors 2, allowing the power of the individualunit linear motors 2 to be collectively utilized, providing high power.

Further, the die linear motor 1A has the slag discharge hole 70 in thearea thereof which coincides with the press drive axis center so thatslag resulting from the press working can be discharged from the slagdischarge hole 70. Slag can thus be smoothly discharged. This preventsthe die linear motor 1A from interfering with discharge of slag eventhough the die linear motor 1A is installed below the hole-making die 61₁. Since the die linear motor 1A is the assembly of the plurality ofunit linear motors 2, the press machine can be easily configured so thatthe slag discharge hole 70 is formed in the press drive axis center.

Further, the present linear motor mounted press machine operates underthe control of the control means 84 in FIG. 1, and as described inconjunction with FIG. 5C, both the punch 61 and the die 62 are drivinglyelevated and lowered for the press working. Thus, various types ofmachining can be performed on the workpiece W by simultaneously drivingboth the punch 61 and the die 62 or sequentially driving the punch 61and the die 62 to machine one point, the shape forming portion Wa. Whenboth the punch 61 and the die 62 are thus drivingly elevated and loweredfor the press working, the excellent controllability of the linearmotors 1, 1A can be effectively utilized. Therefore, accuracy can beeffectively increased by using the linear motors 1, 1A as a drivingsource for both the punch 61 and the die 62.

In the above embodiment, each of the punch linear motor 1 and the dielinear motor 1A comprises the assembly of the plurality of unit linearmotors 2. However, a unitary linear motor that is a single larger unitlinear motor 2 may be used. In this case, the die linear motor 1Apreferably has the slag discharge hole 70 penetrating the center of theshaft member 3, for example, as shown in FIG. 6.

While the present invention has been described with respect to preferredembodiments thereof, it will be apparent to those skilled in the artthat the disclosed invention may be modified in numerous ways and mayassume many embodiments other than those specifically set out anddescribed above. Accordingly, it is intended by the appended claims tocover all modifications of the present invention that fall within thetrue spirit and scope of the invention.

1. A linear motor mounted press machine that presses a workpiece using apunch and a die both located in a press drive axis center, the pressmachine being characterized by comprising a press frame having an upperframe and a lower frame, a punch linear motor provided in the upperframe to drivingly elevate and lower the punch, and a die linear motorprovided in the lower frame to drivingly elevate and lower the die.
 2. Alinear motor mounted press machine according to claim 1, characterizedin that one or both of the punch linear motor and the die linear motorare unit linear motor assemblies each including a plurality of unitlinear motors around the press drive axis center, each of the unitlinear motors having an output shaft that is parallel to the press driveaxis center.
 3. A linear motor mounted press machine according to claim1, characterized in that the die linear motor has a hole in an areathereof which coincides with the press drive axis center, slag resultingfrom the press working being discharged from the hole.
 4. A linear motormounted press machine according to claim 1, characterized in that thedie linear motor is a unit linear motor assembly including a pluralityof unit linear motors around the press drive axis center, each of theunit linear motors having an output shaft that is parallel to the pressdrive axis center, the die linear motor having a hole in an area thereofwhich coincides with the press drive axis center, slag resulting fromthe press working being discharged from the hole.
 5. A linear motormounted press machine according to claim 1, characterized by comprisingcontrol means for drivingly elevating and lowering both the punch andthe die relative to the workpiece for the press working.
 6. A pressworking method for performing a press working on a workpiece by using alinear motor mounted press machine, the method being characterized inthat: the press machine comprises a press frame having an upper frameand a lower frame, a punch linear motor provided in the upper frame todrivingly elevate and lower the punch, and a die linear motor providedin the lower frame to drivingly elevate and lower the die, and themethod performs punching by carrying out both lowering of the punch bymeans of the punch linear motor and elevation of the die by means of thedie linear motor.